Method and System for Selective Equalization Enablement Based on Modulation Type

ABSTRACT

Aspects of a method and system for selective equalization enablement based on modulation type are disclosed. One such method includes receiving a signal via an RF channel, detecting a modulation type of the signal, and selecting an equalization circuit for processing the signal based on the modulation type.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.13/211,111, filed on Aug. 16, 2011, which is a continuation of U.S.application Ser. No. 12/538,444 filed on Aug. 10, 2009, now U.S. Pat.No. 8,000,653, issued on Aug. 16, 2011, which is a continuation of U.S.application Ser. No. 11/112,983, filed on Apr. 11, 2005, now U.S. Pat.No. 7,574,174, issued on Aug. 11, 2009.

This application also makes reference to, claims priority to, and claimsthe benefit of U.S. Provisional Application Ser. No. 60/623,956 filedNov. 1, 2004.

This application also makes reference to U.S. Provisional PatentApplication Ser. No. 60/624,019 filed Nov. 1, 2004.

The above stated applications are hereby incorporated herein byreference in their entirety.

FIELD OF THE INVENTION

Certain embodiments of the invention relate to Bluetooth wirelesscommunications. More specifically, certain embodiments of the inventionrelate to a method and system for selective equalization enablementbased on modulation type.

BACKGROUND OF THE INVENTION

Bluetooth is a short range wireless communications capability thatenables connection between consumer and computer equipment whileeliminating wires. Equipment that is enabled to utilize Bluetoothtechnology may be referred to as Bluetooth devices. Bluetooth deviceswithin a range of approximately 10 meters of each other may communicateutilizing a 2.4 gigahertz frequency band. Examples of Bluetooth devicesmay comprise personal digital assistants (PDA), headsets, telephones,home audio equipment, and computers. Capabilities enabled by Bluetoothtechnology may comprise eliminating cables linking computers toprinters, keyboards, and mouse devices, making calls from a wirelessheadset connected via wireless link to a wired or wireless telephone,and the playing of audio from a portable MP3 player via a homeaudiovisual system with no wired connection between the MP3 player andthe home audiovisual system.

Bluetooth is designed to enable a plurality of Bluetooth devices tooperate in a personal area network (PAN) environment. The plurality ofBluetooth devices in an environment may comprise a network known as apiconet. Within the approximately 10 meter range of Bluetooth technologya plurality of piconets may exist. Thus, Bluetooth technology may enablea plurality of piconets to coexisting within a home environment. Forexample, a first piconet may comprise computer equipment in a homeenvironment, a second piconet may comprise audiovisual equipment in ahome environment, a third piconet may comprise appliances in the homeenvironment such as air conditioners, ovens, and lighting, and so forth.

Traditional Bluetooth enabled Bluetooth devices communicate at datarates of up to 1 megabit per second. Enhanced data rate Bluetooth mayenable Bluetooth devices to communicate at data rates of up to 3megabits per second.

Further limitations and disadvantages of conventional and traditionalapproaches will become apparent to one of skill in the art, throughcomparison of such systems with some aspects of the present invention asset forth in the remainder of the present application with reference tothe drawings.

BRIEF SUMMARY OF THE INVENTION

A system and/or method is provided for selective equalization enablementbased on modulation type, substantially as shown in and/or described inconnection with at least one of the figures, as set forth morecompletely in the claims.

These and other advantages, aspects and novel features of the presentinvention, as well as details of an illustrated embodiment thereof, willbe more fully understood from the following description and drawings.

BRIEF DESCRIPTION OF SEVERAL VIEWS OF THE DRAWINGS

FIG. 1 a is an exemplary illustration of signals for frequency shiftkeying, which may be utilized in connection with an embodiment of theinvention.

FIG. 1 b is an exemplary illustration of frequency shift keying, whichmay be utilized in connection with an embodiment of the invention.

FIG. 1 c is an exemplary illustration of Gaussian frequency shiftkeying, which may be utilized in connection with an embodiment of theinvention.

FIG. 1 d is an exemplary illustration of signals for phase shift keying,which may be utilized in connection with an embodiment of the invention.

FIG. 1 e is an exemplary illustration of phase shift keying, which maybe utilized in connection with an embodiment of the invention.

FIG. 2 is an exemplary illustration of equalization of a receivedsignal, which may be utilized in connection with an embodiment of theinvention.

FIG. 3 is a block diagram illustrating a system for selectiveequalization enablement based on modulation type, in accordance with anembodiment of the invention.

FIG. 4 is a flowchart illustrating exemplary steps for a system forselective equalization enablement based on modulation type, inaccordance with an embodiment of the invention.

DETAILED DESCRIPTION OF THE INVENTION

Certain embodiments of the invention may be found in a method and systemfor selective equalization enablement based on modulation type. Aspectsof a method and system for selective equalization enablement based onmodulation type may be found in a method for processing a radiofrequency (RF) signal that comprises receiving a Bluetooth signal via anRF channel, detecting a modulation type of the received Bluetoothsignal, and selecting an equalization circuit for processing thereceived Bluetooth signal based on the detected modulation type. Themethod may also comprise determining a data rate based on the detectedmodulation type.

FIG. 1 a is an exemplary illustration of signals for frequency shiftkeying, which may be utilized in connection with an embodiment of theinvention. With reference to FIG. 1 a, there is shown a mark signal 102,and a space signal 104. In operation, frequency shift keying (FSK) maybe utilized as a modulation type to transmit data by selecting afrequency of a carrier signal from one of a plurality of frequencies.For example, in binary FSK, one frequency may be identified as a markfrequency 102, while another frequency may be identified as the spacefrequency 104. In many conventional embodiments of binary FSK, the markfrequency 102 may represent a binary 1, while the space frequency 104may represent a binary 0.

FIG. 1 b is an exemplary illustration of frequency shift keying, whichmay be utilized in connection with an embodiment of the invention. Withreference to FIG. 1 b, there is shown a binary sequence 106, an FSKmodulated signal 108, and a plurality of signal transitions 108 a, 108b, 108 c, 108 d, 108 e, and 108 f. A sequence comprising a plurality ofbinary bits indicated as 0's and 1's may be indicated in the binarysequence 106. Also shown in the binary sequence 106 may be a square wavesignal representation of the plurality of binary bits. The binarysequence 106 may be transmitted via a radio frequency (RF) channel as anFSK modulated signal 108. The frequency of the FSK modulated signal 108may be equal to that of the space signal 104 when a binary 0 is beingtransmitted. The frequency of the FSK modulated signal 108 may be equalto the mark signal 102 when a binary 1 is being transmitted.

In the FSK modulated signal 108, some transitions from transmitting abinary 0 to transmitting a binary 1, or vice versa, may occur in-phase,such as, for example, signal transitions 108 a, 108 e, and 108 f.In-phase signal transitions may occur when the value of the signal levelmark frequency 102 at the time of the transition is equal to the valueof the signal level of the space frequency 104. For signal transitions108 b, 108 c, and 108 d, the value of the signal level of the markfrequency 102 at the time of the transition may not be equal to thevalue of the signal level of the space frequency 104. At these timesthere may be discontinuity in the signal level of the FSK modulatedsignal 108, which may represent a sudden change in the signal level ofthe FSK modulated signal 108. These discontinuities may be representedby vertical lines that connect the discontinuous signal levels at signaltransitions 108 b, 108 c, and 108 d. Discontinuities in the FSKmodulated signal 108 may comprise high frequency components that mayreduce the spectral efficiency of signal transmission. As a result, alarger frequency bandwidth may be required to support transmission ofinformation at a given data rate.

FIG. 1 c is an exemplary illustration of Gaussian frequency shiftkeying, which may be utilized in connection with an embodiment of theinvention. With reference to FIG. 1 c, there is shown a binary sequence106, a Gaussian FSK (GFSK) modulated signal 110, and a plurality ofsignal transitions 110 a, 110 b, 110 c, 110 d, 110 e, and 110 f. Thebinary sequence 106 may be transmitted via a radio frequency (RF)channel as a GFSK modulated signal 110. The frequency of the GFSKmodulated signal 110 may be equal to that of the space signal 104 when abinary 0 is being transmitted. The frequency of the GFSK modulatedsignal 110 may be equal to the mark signal 102 when a binary 1 is beingtransmitted.

The GFSK modulated signal 110 may by generated by processing an FSKmodulated signal 108 by a Gaussian filter. The Gaussian filter mayfilter some high frequency components in the FSK modulated signal 108.This may result in a GFSK modulated signal 110 in which signal levelsmay change less rapidly.

In the GFSK modulated signal 110, some transitions from transmitting abinary 0 to transmitting a binary 1, or vice versa, may occur in-phase,such as, for example, signal transitions 110 a, 110 e, and 110 f. Forsignal transitions 110 b, 110 c, and 110 d, the value of the signallevel of the mark frequency 102 at the time of the transition may not beequal to the value of the signal level of the space frequency 104. Atthese times the transition in the signal level of the GFSK modulatedsignal 110 may represent a less sudden change in the signal level thanmay be observed for signal transitions 108 b, 108 c, and 108 d.

The filtering of high frequency components may also produce a GFSKmodulated signal 110 characterized by a greater spectral efficiency thanmay be observed in the FSK modulated signal 108. Consequently, the GFSKmodulated signal 110 may permit transmission of information at a givenrate to be achieved with a lower required frequency bandwidth.

FIG. 1 d is an exemplary illustration of signals for phase shift keying,which may be utilized in connection with an embodiment of the invention.With reference to FIG. 1 d, there is shown a first phase signal 112, anda second phase signal 114. In operation, phase shift keying (PSK) may beutilized as a modulation type to transmit data by selecting a phase of acarrier signal at a given frequency from one of a plurality of phases.For example, in binary PSK, the first phase signal 112 may represent asignal comprising a phase shift of 0, while a second phase signal 114may represent a signal comprising a phase shift of 180 degrees. Thefirst phase signal 112 may represent a binary 0, while the second phasesignal 114 may represent a binary 1.

FIG. 1 e is an exemplary illustration of phase shift keying, which maybe utilized in connection with an embodiment of the invention. Withreference to FIG. 1 e, there is shown a binary sequence 116, a PSKmodulated signal 118, and a plurality of signal transitions 118 a, 118b, 118 c, and 118 d. A sequence comprising a plurality of binary bitsindicated as 0's and 1's may be indicated in the binary sequence 116.Also shown in the binary sequence 116 may be a square wave signalrepresentation of the plurality of binary bits. The binary sequence 116may be transmitted via a radio frequency (RF) channel as a PSK modulatedsignal 118. The phase of the PSK modulated signal 118 may be equal tothat of the first phase signal 112 when a binary 0 is being transmitted.The phase of the PSK modulated signal 118 may be equal to the secondphase signal 114 when a binary 1 is being transmitted.

A Bluetooth signal may utilize GFSK. Information communicated in aBluetooth signal may be transmitted at a data rate of up to 1 megabitper second (Mbit/s). Enhanced data rate Bluetooth, which may also beknown as EDR Bluetooth, or Bluetooth EDR, may achieve information datarates of 3 Mbits/s. EDR Bluetooth may utilize PSK. EDR Bluetooth mayrequire that the Bluetooth signal be processed by equalization tocompensate for transmission impairments that may occur in an RF channelfor a Bluetooth signal characterized by data rates in excess of 1Mbit/s.

FIG. 2 is an exemplary illustration of equalization of a receivedsignal, which may be utilized in connection with an embodiment of theinvention. With reference to FIG. 2, there is shown a received signal202, an equalizer response curve 204, and a desired signal 206. Thereceived signal 202 may represent a received RF signal based on anoriginal transmitted signal. The equalizer response curve 204 mayrepresent an equalizer response function for an equalizer circuit. Thebehavior represented by the equalizer response curve 204 may vary as afunction of frequency. In this aspect, the equalizer response curve 204may behave in such a manner that amplifies processed signals at certainfrequencies while attenuating processed signals at other frequencies.The desired signal 206 may represent a desired received signal based onan original transmitted signal. Due to transmission impairments in an RFchannel, a received signal 202 may represent the original transmittedsignal at certain frequencies, but may not represent the originaltransmitted signal at other frequencies. An equalizer circuit mayutilize an equalizer response function, as represented by the equalizerresponse curve 204, to process the received signal 202 to generate adesired signal 206, which may represent the original transmitted signalover a wider range of frequencies. Embodiments of the invention may notbe limited in the method of equalization utilized to process a receivedsignal, such as, for example, received signal 202.

FIG. 3 is a block diagram illustrating a system for selectiveequalization enablement based on modulation type, in accordance with anembodiment of the invention. The elements shown in FIG. 3 may comprisecomponents that may be present in, for example, an embodiment of aBluetooth receiver, which may also be referred to as a receiver. Theelements shown in FIG. 3 may comprise components that may be present inan exemplary embodiment of a Bluetooth transmitter, which may also bereferred to as a transmitter. A Bluetooth transceiver, which may also bereferred to as a transceiver, may comprise components of a Bluetoothreceiver and a Bluetooth transmitter that have been adapted andcollocated in a single device. Embodiments of the invention may comprisea Bluetooth receiver, a Bluetooth transmitter, and a Bluetoothtransceiver. Referring to FIG. 3 there is shown anti-aliasing filter(AAF) 302, a direct digital frequency synthesizer (DDFS) 304, a low passfilter (LPF) 306, an equalizer (EQ) switch 308, an equalizer 310, aselector (SEL) 312, a coordinate rotation digital computer (CORDIC) 314,a slicer 315, a baseband processor 316, a receiver front end (RFE) 318,and a frequency mixer 320.

The RFE 318 may comprise suitable logic, circuitry and/or code that maybe adapted to receiving a Bluetooth signal transmitted via an RFchannel, or transmitting a Bluetooth signal via an RF channel. The RFE318 may downconvert a received RF signal to an input intermediatefrequency (IF) signal, and/or may upconvert an output IF signal to an RFsignal for transmission an RF channel. The RFE 318 may comprise anantenna, filtering, and analog to digital conversion (A/D) circuitrythat may generate a received IF (IF_(rec)) signal. The signal IF_(rec)may comprise a digital signal.

The AAF 302 may comprise suitable logic, circuitry and/or code that maybe adapted to improve the quality of a received IF (IF_(rec)) signal byperforming anti alias filtering to condition the received IF signalIF_(rec) to reduce aliasing that may be present in the received signal.The AAF 302 may produce an anti alias filtered signal IF′_(rec) that maycomprise improvements based on the received IF signal IF_(rec).

The DDFS 304 may comprise suitable logic, circuitry and/or code that maybe adapted to generate signals at a frequency that may be utilized todownconvert the active filtered signal IF′_(rec) to t basebandfrequency. The DDFS 304 may generate an intermediate frequency signal,f_(IF).

The frequency mixer 320 may comprise suitable logic, circuitry, and/orcode that may be adapted to utilize an intermediate frequency signalf_(IF) to generate a baseband signal by downconverting an anti aliasfiltered signal IF′_(rec) from the AAF 302. After downconversion, thereceived signal may be represented as signals comprising an in-phasecomponent signal, I_(SB), and a quadrature component signal, Q_(SB).

The LPF 306 may comprise suitable logic, circuitry, and/or code that maybe adapted to downsample digital signals I_(SB) and Q_(SB) comprising aplurality of digital samples of an analog signal. The LPF 306 mayproduce low pass filtered signals comprising an in-phase component, I,and a quadrature component Q. The digital signal I may comprise fewerdigital samples and a narrower frequency spectrum than the correspondingdigital signal I_(SB). The digital signal Q may comprise fewer digitalsamples and a narrower frequency spectrum than the corresponding digitalsignal Q_(SB).

The EQ Switch 308 may comprise suitable logic, circuitry, and/or codethat may be adapted to receive I and Q signals at the input of the EQswitch 308, and coupling the I and Q signals to the output of the EQswitch 308 based on a data_rate signal.

The EQ 310 may be adapted to perform equalization on I and Q signalsreceived at the input of the EQ 310 to improve signal quality of theinput I and Q signals. The EQ 310 may apply an equalizer response curve,such as, for example the equalizer response curve 204, to the input Iand Q signals to generate equalized signals I_(EQ) and Q_(EQ)respectively.

The SEL 312 may comprise suitable logic, circuitry, and/or code that maybe adapted to select from a plurality of pairs of input signalscomprising I and Q, and I_(EQ) and Q_(EQ), based on a select signalwhich may be referred to as the data_rate signal. The selected nonequalized baseband signals I and Q, or equalized baseband signals I_(EQ)and Q_(EQ) may be coupled to the selector output signals I_(SEL) andQ_(SEL) respectively.

The CORDIC 314 may comprise suitable logic, circuitry, and/or code thatmay be adapted to analyze input signals I_(SEL) and Q_(SEL) and toextract information content which may be contained in the input signalsI_(SEL) and Q_(SEL). The CORDIC 314 may generate complex phaseinformation based on the input signals I_(SEL) and Q_(SEL).

The slicer 315 may comprise suitable logic, circuitry, and/or code thatmay be adapted to reconstitute bits of binary information based oncomplex phase information. The slicer 315 may map received complex phaseinformation to a specific constellation point based on a modulationtype. The constellation point may correspond to a representation of oneor more binary bits of information. The slicer 315 may output the binarybits of information.

The baseband processor 316 may comprise suitable logic, circuitry,and/or code that may be adapted process the binary bits generated by theslicer 315. The baseband processor may structure a plurality of binarybits to form a media access control layer protocol data unit (MAC PDU).The baseband processor may analyze the binary information in a receivedMAC PDU.

In operation, an incoming Bluetooth signal may be received via an RFchannel by an antenna at an RFE 318. The RFE 318 may process thereceived RF signal to generate a received IF signal IF_(REC). The AAF302 may perform anti alias filtering of the received RF signal togenerate an anti alias filtered signal IF′_(rec). The anti aliasfiltered signal IF′_(rec) may be communicated to the frequency mixer320. The DDFS 304 may generate an intermediate frequency signal, f_(IF).The receiver frequency carrier signal f_(IF) may be communicated to thefrequency mixer 320.

The frequency mixer 320 may process the active filtered signal IF′_(rec)utilizing the intermediate frequency signal f_(CR) to generate abaseband signal. An original Bluetooth signal may have been a basebandsignal, s, prior to transmission via an RF channel. The baseband signalmay have been modulated by a transmitter signal f_(CT) to generate an IFsignal, s(f_(CT)) that may be transmitted via an RF channel. Thereceived IF′_(rec) signal, ŝ(f_(CT)), may be processed by the frequencymixer 320 to extract the baseband signal, ŝ. The frequency mixer 320 mayprocess the received RF signal ŝ(f_(CT)) to generate signals at aplurality of carrier frequencies. The frequency mixer may generate afirst version of the baseband signal ŝ which has been modulated at afrequency equal to the difference of the frequencies of the transmittersignal and the receiver intermediate frequency signal f_(CT)−f_(CR),ŝ(f_(CT)−f_(CR)). The frequency mixer may generate a second version ofthe baseband signal ŝ which has been modulated at a frequency equal tothe sum of the frequencies of the transmitter signal and the receiverintermediate frequency signal f_(CT)+f_(CR), ŝ(f_(CT)−f_(CR)). The firstversion of the baseband signal ŝ generated by the frequency mixer 320may comprise a received baseband signal. Based on the signalsŝ(f_(CT)−f_(CR)) and ŝ(f_(CT)+f_(CR)) the frequency mixer 320 maygenerate an in-phase signal I_(SB), and a quadrature signal Q_(SB). Thein-phase signal I_(SB), and a quadrature signal Q_(SB) may comprisefrequency components f_(CT)−f_(CR) and f_(CT)+f_(CR). The frequencyequal to the difference of the frequencies of the transmitter carriersignal and the receiver carrier signal f_(CT)−f_(CR) may represent alower frequency than that of the frequency equal to the sum of thefrequencies of the transmitter carrier signal and the receiver carriersignal f_(CT)+f_(CR).

The LPF 306 may process the in-phase signal I_(SB), and quadraturesignal Q_(SB) to suppress the f_(CT)+f_(CR) frequency component. The LPF306 may generate an in-phase signal I, and a quadrature signal Q with apredominant frequency component equal to the difference of thefrequencies of the transmitter carrier signal and the receiver carriersignal f_(CT)−f_(CR). These signals, the in-phase signal I, and thequadrature signal Q, may comprise a received baseband signal.

The baseband processor 316 may receive binary bits from the slicer 315.The baseband processor 316 may structure a plurality of received binarybits to form a MAC layer PDU. The baseband processor 316 may analyze thecontents of the MAC layer PDU. At the start of a communication with apeer Bluetooth device, via an RF channel, the baseband processor 316 mayexchange information with the peer Bluetooth device to establish themodulation type that will be utilized to exchange subsequentinformation. The exchange of information to determine the modulationtype is based on Bluetooth standards. The MAC PDUs received by thebaseband processor 316 during this phase may comprise information thatmay be utilized to establish the modulation type. At the start of acommunication GFSK modulation may be utilized to transmit informationvia the RF channel. When GFSK modulation is utilized, the selector 312may select the low pass filtered signals I and Q to be communicated tothe CORDIC 314. To enable this selection, the baseband processor 316 maygenerate a data_rate signal that instructs the selector SEL 312 toselect the I and Q signals and to communicate those signals to theCORDIC 314. The data_rate signal may also instruct the EQ switch 308 toconfigure the EQ 310 in a power OFF state.

The CORDIC 314 may generate a complex phase signal based on the basebandsignals I_(SEL) and Q_(SEL) from the SEL 312. The slicer 315 may utilizethe generated complex phase signal to generate binary bits. As thebaseband processor 316 receives and analyzes received binary bits,information may be extracted that may be utilized to determine themodulation type to exchange subsequent information. When PSK modulationis utilized the data rate for subsequent information exchange may exceed1 Mbit/s. When GFSK modulation is utilized the data rate for subsequentinformation exchange may not exceed 1 Mbit/s. If the modulation typeindicates that the data rate utilized for subsequent information exceeds1 Mbit/s, the baseband processor may generate a data_rate signal thatinstructs the SEL 312 to select the equalized baseband signals I_(EQ)and Q_(EQ). The data_rate signal may also instruct the EQ switch 308 toconfigure the equalizer EQ 310 in a power ON state.

The EQ 312 may perform equalization on the baseband signals I and Q toimprove the signal quality of the baseband signals. The EQ 312 maydetermine a process by which to improve the baseband signals I and Qbased on, for example, a training sequence that may have beencommunicated in a Bluetooth signal received via an RF channel. Thetraining sequence may comprise well-known information such that the EQ312 may compare the information actually received in the trainingsequence via an RF channel in relation to the information that wasexpected based on the well-known information. Information derived duringthe training sequence may enable the EQ 312 to characterize thefrequency response of the received signal, for example, as in thereceived signal 202 (FIG. 2). From this information, the EQ 312 maydetermine an equalizer response curve, for example, the equalizerresponse curve 204, which may be utilized to process subsequentlyreceived Bluetooth signals via the same RF channel. Equalization of thebaseband signals I and Q may correct errors introduced in the receivedbaseband signal, ŝ, due to transmission impairments in the RF channelthat may produce differences between the information contained in thereceived baseband signal, ŝ, and the information contained in theoriginally transmitted baseband signal s. After processing the basebandsignals I and Q, the EQ 310 may generate equalized baseband signalsI_(EQ) and Q_(EQ). If the select signal data_rate has enabled the EQswitch 308 and the EQ 310 to process the baseband signals I and Q, thedata_rate signal may control the SEL 312 to couple the equalizedbaseband signals I_(EQ) and Q_(EQ) from the EQ 310 to inputs to theCORDIC 314.

The baseband processor 316 may receive subsequent information comprisingbinary bits from the slicer 315. The binary bits may be extracted frombaseband signals I and Q that may be processed based on the data_ratesignal. The baseband processor 316 may structure the plurality ofreceived binary bits from received subsequent information to form a MAClayer PDU. The baseband processor 316 may analyze the contents of theMAC layer PDU.

FIG. 4 is a flowchart illustrating exemplary steps for a system forselective equalization enablement based on modulation type, inaccordance with an embodiment of the invention. Referring to FIG. 4, instep 402, the baseband processor 316 (FIG. 3) may determine themodulation type and data rate for subsequent information. In step 404, aBluetooth signal may be received comprising subsequent information. Step406 may determine whether the data rate is greater than 1 Mbit/s. If thedata rate is greater than 1 Mbit/s, step 410 may set the equalizerswitch 308 to couple the received baseband signals I and Q to inputs atthe equalizer 310. In step 412, the equalizer 310 may be turned ON. Instep 414, the baseband signals I and Q signals may be equalized togenerate the baseband signals I_(EQ) and Q_(EQ). In step 416, theequalized baseband signals I_(EQ) and Q_(EQ) may be communicated to theCORDIC 416 via the selector SEL 312. If the data rate is determined tobe not greater than 1 Mbit/s in step 408, the equalizer 310 may beturned OFF. In step 416, the baseband I and Q signals generated by theLPF 306 may be communicated to the CORDIC 314 via the SEL 312.

Various embodiments of the invention described herein may enable aBluetooth receiver, transmitter, or transceiver to selectively enableequalization based on a modulation type. The modulation type mayindicate the data rate of information being communicated in a Bluetoothsignal. Therefore, various embodiments of the invention may enable aBluetooth receiver, transmitter, or transceiver to selectively enableequalization based on a data rate. If the data rate is not greater than1 Mbit/s, an equalizer may be disabled from processing the receivedBluetooth signal. If the data rate is greater than 1 Mbit/s, theequalizer may be enabled to process the Bluetooth signal. If the datarate is not greater than 1 Mbit/s, the output may represent a low passfiltered received Bluetooth signal that has not been processed byequalization. If the data rate is greater than 1 Mbit/s, the output mayrepresent a low pass filtered received Bluetooth signal that has beenprocessed by equalization.

An aspect of the invention is that the utilization of an equalizer mayenable a Bluetooth receiver, transmitter, or transceiver to achievebetter performance as measured by, for example, information throughputrate, or bit error rate, for received Bluetooth signals in a receiver ortransceiver, or for transmitted Bluetooth signals, in a transmitter ortransceiver. Another aspect of the invention is that an equalizer switchmay reduce power consumption in the Bluetooth receiver, transmitter, ortransceiver by configuring the equalizer in a turned OFF state when theequalizer is disabled based on the data rate, and configuring theequalizer in a turned ON state when the equalizer is enabled based onthe data rate.

In some conventional systems, no equalization may be performed on areceived Bluetooth signal. Such systems may provide a lower level ofperformance for data rates that are greater than 1 Mbit/s. In otherconventional systems, equalization may be performed on all receivedBluetooth signals. Such systems may require an unnecessarily high levelof power consumption because equalization of Bluetooth signals with datarates that are not greater than 1 Mbit/s may not provide a higher levelof performance than systems that perform no equalization at data ratesthat are not greater than 1 Mbit/s. Various embodiments of the inventionthat utilize the selective enablement of equalization based onmodulation type may enable a Bluetooth receiver, transmitter, ortransceiver to maximize performance and minimize power consumption overa range of data rates.

Aspects of a system for processing a radio frequency (RF) signal maycomprise circuitry that receives a Bluetooth signal via an RF channel,and a baseband processor that detects a modulation type of the receivedBluetooth signal. The baseband processor may select an equalizationcircuit for processing the received Bluetooth signal based on thedetected modulation type. The baseband processor may determine a datarate of the received Bluetooth signal based on the detected modulationtype. The equalization circuit may equalize the received Bluetoothsignal based on a determined data rate. The baseband processor mayenable the equalization circuit via a switch. The equalization circuitmay process the received Bluetooth signal based on the detectedmodulation type.

Other aspects of the system may comprise an equalizer switch thatenables the equalization circuit for processing of the receivedBluetooth signal, if a detected data rate of the detected modulationtype is greater than about 1 megabit per second. The equalizer switchmay disable the equalization circuit for processing of the receivedBluetooth signal, if a detected data rate of the detected modulationtype is less than about 1 megabit per second. The equalizer switch mayconfigure the equalization circuit in a power turned OFF state. Aselector circuit may select an output signal based on the detectedmodulation type. The selector circuit may select the output signal froman equalized received Bluetooth signal, if a detected data rate of thedetected modulation type is greater than about 1 megabit per second. Theselector circuit may select the output signal from a non-equalizedreceived Bluetooth signal, if a detected data rate of the detectedmodulation type is less than about 1 megabit per second.

Accordingly, the present invention may be realized in hardware,software, or a combination of hardware and software. The presentinvention may be realized in a centralized fashion in at least onecomputer system, or in a distributed fashion where different elementsare spread across several interconnected computer systems. Any kind ofcomputer system or other apparatus adapted for carrying out the methodsdescribed herein is suited. A typical combination of hardware andsoftware may be a general-purpose computer system with a computerprogram that, when being loaded and executed, controls the computersystem such that it carries out the methods described herein.

The present invention may also be embedded in a computer programproduct, which comprises all the features enabling the implementation ofthe methods described herein, and which when loaded in a computer systemis able to carry out these methods. Computer program in the presentcontext means any expression, in any language, code or notation, of aset of instructions intended to cause a system having an informationprocessing capability to perform a particular function either directlyor after either or both of the following: a) conversion to anotherlanguage, code or notation; b) reproduction in a different materialform.

While the present invention has been described with reference to certainembodiments, it will be understood by those skilled in the art thatvarious changes may be made and equivalents may be substituted withoutdeparting from the scope of the present invention. In addition, manymodifications may be made to adapt a particular situation or material tothe teachings of the present invention without departing from its scope.Therefore, it is intended that the present invention not be limited tothe particular embodiment disclosed, but that the present invention willinclude all embodiments falling within the scope of the appended claims.

1. A method comprising: receiving a signal via an radio frequency (RF)channel; detecting a modulation type of the signal; selecting anequalization circuit based at least in part on the modulation type; andproviding the signal to the equalization circuit.
 2. The methodaccording to claim 1, further comprising determining a data rate of thesignal based at least in part on the detected modulation type.
 3. Themethod according to claim 1, further comprising equalizing the signalbased at least in part on a determined data rate.
 4. The methodaccording to claim 1, further comprising equalizing the signal based atleast in part on the detected modulation type.
 5. The method accordingto claim 1, further comprising enabling the equalization circuitresponsive to a detected data rate of the modulation type being greaterthan about 1 megabit per second.
 6. The method according to claim 1,further comprising disabling the equalization circuit responsive to adetected data rate of the modulation type being less than about 1megabit per second.
 7. A system comprising: circuitry operable toreceive a signal via an radio frequency (RF) channel; and a basebandprocessor operable to detect a modulation type of the signal and toselect an equalization circuit based at least in part on the modulationtype.
 8. The system according to claim 7, wherein the baseband processoris further operable to determine a data rate of the signal based atleast in part on the modulation type.
 9. The system according to claim7, wherein the equalization circuit is operable to equalize the signalbased on a determined data rate.
 10. The system according to claim 7,wherein the baseband processor is further operable to control theequalization circuit via a switch.
 11. The system according to claim 7,wherein the equalization circuit is operable to process the signal basedon the detected modulation type.
 12. The system according to claim 11,further comprising a switch operable to enable the equalization circuitin response to a detected data rate of the detected modulation typebeing greater than about 1 megabit per second.
 13. The system accordingto claim 11, further comprising a switch operable to disable theequalization circuit in response to a detected data rate of the detectedmodulation type being less than about 1 megabit per second.
 14. Thesystem according to claim 13, wherein the switch is operable to disablethe equalization circuit by setting the equalization circuit to a powerturned OFF state.
 15. The system according to claim 7, wherein thebaseband processor is further operable to provide the signal to aselector circuit that is operable to select an output signal based onthe modulation type.
 16. The system according to claim 15, wherein theselector circuit is further operable to select, as the output signal, anequalized form of the signal in response to a detected data rate of themodulation type being greater than about 1 megabit per second.
 17. Thesystem according to claim 15, wherein the selector circuit is furtheroperable to select, as the output signal, a non-equalized form of thesignal in response to a detected data rate of the detected modulationtype being less than about 1 megabit per second.
 18. A devicecomprising: a baseband processor configured by instructions executingthereon to: detect a modulation type of a signal received via an radiofrequency (RF) channel; control an equalization circuit based at leastin part on the modulation type; and provide the signal to theequalization circuit.
 19. The device according to claim 18, wherein thebaseband processor is further configured by the instructions to controlthe equalization circuit such that the equalization circuit outputs anequalized form of the signal in response to a detected data rate of themodulation type being greater than about 1 megabit per second.
 20. Thedevice according to claim 18, wherein the baseband processor is furtherconfigured by the instructions to control the equalization circuit suchthat the equalization circuit outputs a non-equalized form of the signalin response to a detected data rate of the detected modulation typebeing less than about 1 megabit per second.